James MacMullen

Development of flax/carbon fibre hybrid composites for enhanced properties

Uni-directional (UD) and cross-ply (CP) cellulosic flax fibre epoxy composites were produced by hybridising UD carbon fibre prepreg onto flax system. A compression moulding technique was used to produce both flax and carbon/flax hybridised laminates. The effect of carbon fibre hybridisation on the water absorption behaviour, thermal and mechanical properties of both UD and CP flax specimens were investigated by means of water absorption, tensile, thermogravemetric analysis and flexural testing. The results showed that water absorption behaviour of hybrid samples are markedly improved compared to those without hybridisation. Similarly, the thermal stability, tensile and flexural properties of the hybrid composites are significantly improved in comparison with UD and CP flax composites without hybridisation. The experimental results suggest that cellulosic flax fibre reinforcement contributed to improve the toughness properties by promoting crack propagation whereas the carbon fibre contributed in improving thermal stability, water absorption behaviour and the overall strength and the stiffness of the hybrid composites.

Moisture measurement and effects on properties of marine composites

Natural fibre composites have recently attracted a great deal of attention by the marine industry due to their many attractive benefits for structural applications. Beneficial properties include; high strength-to-weight ratio, sustainable characteristics and low cost. These materials unfortunately are highly susceptible to moisture ingress which can lead to inferior thermo-mechanical properties and structural failure. These failure routes may be diverse and difficult to detect therefore adequate material selection, processing, and testing is paramount in achieving a long lasting functional marine structure. This chapter focuses on the investigation of these imparted moisture related attributes and their influence on properties.